In the prior art there are disclosed numerous systems for diverting fish and other aquatic life from water intakes. Most of these systems deal with different intake designs. U.S. Pat. No. 4,064,048 issued Dec. 20, 1977 to Downs et al., which is incorporated herein by reference, teaches the use of louvers, U.S. Pat. No. 6,051,131 issued Apr. 18, 2000 to Maxson, which is incorporated herein by reference, teaches the use of submerged intake screens, U.S. Pat. No. 5,385,428 issued Jan. 31, 1995 to Taft, 3rd et al., which is incorporated herein by reference, teaches the use of a plane screen, U.S. Pat. No. 4,415,462 issued Nov. 15, 1983 to Finch, et al., which is incorporated herein by reference, teaches the use of a self-cleaning screen, U.S. Pat. No. 6,457,436 issued Oct. 1, 2002 to Truebe, et al., which is incorporated herein by reference, teaches the use of paddlewheels, and (U.S. Pat. No. 4,594,024 issued Jun. 10, 1986 to Jenkner, et al., which is incorporated herein by reference, teaches the use of an offshore intake).
For example Downs, et al. describe a water flow system for diverting fish and debris using a plurality of vertically extended, laterally spaced louver members. A diversion structure is located at one end of the louver system before diverting fish back into the water. U.S. Pat. No. 4,169,792 issued Oct. 2, 1979 to Dovel, which is incorporated herein by reference, describes a water intake device comprising a cylindrical rotatable screen which is designed to guide or carry fish and debris away from entering the screen. Finch, et al teaches a self-cleaning screen system for use at hydro-electric stations whereas Taft, 3rd et al., teach a fish diversion apparatus which uses a plane screen to divert fish from different intake flows. None of these inventions teach a porous dike concept or means of excluding fish using small passages through the intake structure. There are also no means of preventing attachment due to mollusks such as zebra mussels or related species through these passages.
Similarly, patents on porous dikes or breakwaters do not teach means of reducing fish passage or ways of preventing attachment from zebra mussels and related species. For example, U.S. Pat. No. 5,123,780 issued Jun. 23, 1992 to Martinsen, which is incorporated herein by reference, teaches the use of prefabricated concrete blocks for constructing a breakwater or dike not an water intake for reducing fish passage or preventing mussel attachment.
The recent introduction of zebra mussels to North American waterways is problematic for porous dikes and related systems due to clogging resulting from mussel attachment (Claudi and Mackie 1976). There are also prior art methods for controlling zebra mussels, however, some of these are potentially harmful to the environment, and are not necessarily compatible with prior art fish diversion systems. Recent USEPA 316B environmental legislation as part of the Clean Water Act makes it imperative that a solution be found.